People with type 1 diabetes who have already been successful in achieving recommended blood sugar goals can further benefit from using continuous glucose monitoring (CGM) devices, according to results of a major multi-center clinical trial by the Juvenile Diabetes Research Foundation. Findings of the study were published online by the journal Diabetes Care.
According to the JDRF study, using CGM devices enables people who have achieved excellent control (with HbA1c levels below 7 percent) to continue to tightly manage their diabetes while cutting down on the frequency of low blood sugars, called hypoglycemia. Research has shown that good blood sugar control is a key factor in reducing the risk of the devastating long-term complications of the disease, such as blindness and kidney disease - but that the fear of low blood sugar emergencies often prevents many people from achieving tight control, and remains a constant concern for those who manage their diabetes well. The landmark Diabetes Control and Complications Trial (DCCT) showed that with intensive insulin therapy, excellent blood glucose control was obtained, but at the expense of a considerable increase in hypoglycemia. Today, the JDRF study has shown that, with CGM, hypoglycemia can be reduced while maintaining excellent blood sugar control.
The CGM study was a randomized and controlled trial involving 129 adults and children ranging in age from 8 to 69-years-old at 10 sites, including the Atlanta Diabetes Associates, the Joslin Diabetes Center, Kaiser Permanente Southern California, Nemours Children's Clinic - Jacksonville, FL, the Lucile Packard Children's Hospital at Stanford University, the Barbara Davis Center for Childhood Diabetes at the University of Colorado Denver, the University of Iowa, the University of Washington, and Yale University, and coordinated by the Jaeb Center for Health Research in Tampa, Florida. Participants all had good diabetes control when they enrolled in the trial, and were randomly assigned to either a group that used CGM devices or one using standard finger-stick glucose testing for 26 weeks.
"The research suggests that CGM devices helped people who were already doing an excellent job of managing their diabetes continue to do so, while lowering the risk of pushing their blood sugar so low it causes hypoglycemia, which can be life threatening," said Dr. Bruce Bode, Atlanta Diabetes Associates and one of the lead authors of the Diabetes Care paper. "These trials are showing that CGM not only helps people get into control, which can have a significant positive impact on lowering the risk of complications, but it enables them to stay in control without increasing the near-term risk of hypoglycemia. That's terrific news for people with diabetes and their families."
(People with diabetes try to maintain their blood sugar levels between 70 mg/dL and 180 mg/dL. When blood sugar becomes very low, people can become confused, lethargic, and even slip into a coma or die. Very high blood sugars can also be dangerous. And long term, lack of control increases the risk of developing devastating complications, including eye, kidney, nerve, and heart disease. HbA1c is a measure of long term blood sugar control; standards of good control are generally below 7% for adults, and below 7.5% to 8% for children, depending on age. According to the DCCT findings, every one point reduction in HbA1c reduces the risk of long-term complications by approximately 40%.)
According to the study, for the people using CGM devices the time the blood sugar level was below 70 mg/dL decreased by 37 minutes a day. This compared with a decrease in the control group of only 5 minutes a day. In other words, people in the CGM group spent almost two hours more time per day in the target blood sugar range of 71 to 180 mg/dL compared with the control group, and about half an hour less time per day with glucose values in the potentially dangerous hypoglycemia range. The authors demonstrated a number of other significant benefits in this population including:
- more people in the CGM group had an improvement in HbA1c of more than 0.3% (31% versus 5% in the control group)
- fewer had a worsening of HbA1c greater than 0.3% (28% versus 52%)
- more CGM users had a HbA1c level below 7% at 26 weeks (88% versus 63%)
- more people in the CGM group than the control group had a decrease in HbA1c of more than 0.3% without experiencing a severe hypoglycemic event (28% versus 5%).
Encouragingly, similar beneficial results were seen in children, adolescents, and adults spanning the ages of 8 to 69 years.